Long‐Term Plant Community Development on Topsoil Treatments Overlying a Phytotoxic Growth Medium

Abstract

The application of topsoil over phytotoxic mine waste materials is often the most effective method of establishing and maintaining plant communities during reclamation. However, long-term data on the effectiveness of topsoil cover treatments, as well as on treatments used to enhance vegetation establishment on soil covers, are lacking. Therefore, we evaluated long-term plant community development on study plots in which 60 cm of Paraho retorted oil shale was covered by various depths of topsoil. Each plot was drill seeded with one of three seed mixtures (native, introduced, and combination of native and introduced species), and fertilized with one of three rates of nitrogen (N) and phosphorus (P) fertilizer following plot construction in 1977. Data collected in 1997 showed that native species were as productive as introduced species on deeper topsoil depths and on the control. Also, relative plant species composition and plant species richness continued to be greatly influenced by seed mixture treatments. Plots seeded with a particular seed mixture were still dominated by those species originally seeded, and native seed mixture plots were more species rich than introduced seed mixture plots. Finally, the onetime application of N and P was no longer influencing aboveground biomass.

Long-Term Plant Community Development in Response to Topsoil Replacement Depth on Mined Land in Wyoming

“…Grass and Forb Cover Mean percent grass cover was significantly greater at the 40 and 60 cm topsoil depths compared to the 0 and 20 cm treatments (Figure 1), probably in response to higher nutrient levels and water infiltration and water holding capacity at the deeper depths (Bowen 2003). These findings closely reflect those reported by Syndor and Redente (2000) in northwestern Colorado. In contrast, forb cover was significantly higher at the 0 cm topsoil depth than the other three depths.…”

Long‐Term Effects of Biosolids on Revegetation of Disturbed Sagebrush Steppe in Northwestern Colorado

“…Other long‐term studies at the Piceance Basin site have found that seed mixture composition has a lasting effect on plant community composition (Sydnor & Redente 2000; Newman & Redente 2001). Our results suggest that this is especially true for soils with high initial fertility (topsoil plots) where seeded grasses may quickly establish and dominate the site.…”

“…The topsoil plots were constructed with 61 cm of topsoil material that was mixed thoroughly and placed over retorted oil shale (produced by the Paraho method). The effects of this oil shale on vegetation have been examined for this site by Sydnor and Redente (2000). The subsoil plots were constructed with 122 cm of mixed subsoil material placed over a preexisting soil substrate.…”

Growth and nutrient uptake of arbuscular mycorrhizal maize in different depths of soil overlying coal fly ash

“…However, greater depths may be advisable and further work is required to determine the optimum soil depth under field conditions. Long-term studies on perennial vegetation introduced on topsoil of depths 30, 60, and 90 cm overlying retorted oil shale in Colorado showed that total above ground biomass was greatest on deeper topsoils (Sydnor and Redente, 2000). Although transportation of topsoil is expensive, the remediated areas will require substantial annual inputs of fertilizers to maintain agricultural productivity, and the cost of applying extra soil may be cost-effective in the long term.…”